Document more uses of $cross_compiling.

* doc/autoconf.texi (Runtime): Document that a temporary override
is permissible.
* THANKS: Update.
Reported by Ineiev, example by Ralf Wildenhues.

Signed-off-by: Eric Blake <ebb9@byu.net>

diff --git a/ChangeLog b/ChangeLog
index 97e8ddc54205a6be511ab4e68bb92b0084c2eb0b..ef48fbffb928abab94fa320f1831e39934c83676 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 2008-03-21  Eric Blake  <ebb9@byu.net>
 
+       Document more uses of $cross_compiling.
+       * doc/autoconf.texi (Runtime): Document that a temporary override
+       is permissible.
+       * THANKS: Update.
+       Reported by Ineiev, example by Ralf Wildenhues.
+
        Don't swallow $1 in textual local variables.
        * lib/m4sugar/m4sugar.m4 (m4_combine): Don't use overquoting and
        expansion of text arguments, as that swallows $1.

diff --git a/THANKS b/THANKS
index 84d2cdbab14e3817badb3518ca4c54649e3a9541..a561cfbb88e99ae2179febace0ca09b61f004fd0 100644 (file)
--- a/THANKS
+++ b/THANKS
@@ -139,6 +139,7 @@ Ian Lance Taylor            ian@cygnus.com
 Ian Macdonald               iamacdo@telkomsa.net
 Ian Redfern                 Ian.Redfern@logicacmg.com
 Ilya Zakharevich            ilya@Math.Berkeley.EDU
+Ineiev                      ineiev@yahoo.co.uk
 Iohannes m zmoelnig         zmoelnig@iem.at
 J C Fitzgerald              v7022@wave.co.nz
 Jaap Haitsma                jaap@haitsma.org

diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index 0710397f9b7fb9ac0c32e77cdafc1af8ab8ca3cd..a32e7790bd6f1e5bb3342cdb4b898e59f21c4c93 100644 (file)
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -8371,6 +8371,21 @@ you can test whether the shell variable @code{cross_compiling} is set to
 @samp{yes}, and then use an alternate method to get the results instead
 of calling the macros.
 
+It is also permissible to temporarily assign to @code{cross_compiling}
+in order to force tests to behave as though they are in a
+cross-compilation environment, particularly since this provides a way to
+test your @var{action-if-cross-compiling} even when you are not using a
+cross-compiler.
+
+@example
+# We temporarily set cross-compile mode to force AC_COMPUTE_INT
+# to use the slow link-only method
+save_cross_compiling=$cross_compiling
+cross_compiling=yes
+AC_COMPUTE_INT([@dots{}])
+cross_compiling=$save_cross_compiling
+@end example
+
 A C or C++ runtime test should be portable.
 @xref{Portable C and C++}.